Multiple stage rocket



March 8, 1960 J. KAYE ETAL MULTIPLE STAGE ROCKET Filed May 13, 1958 2 Sheets-Sheet l Fig. I

INVENTORS JOSEPH KAYE EDWARD F. KURTZ JR. GEORGE F. HARPE BY ENWAY. JENNEY. WITTER & HILDREFH ATTORNEYS J. KAYE ET AL MULTIPLE STAGE ROCKET March 8, 1960 2 Sheets-Sheet 2 Filed May 15, 1958 INVENTORS JOSEPH KAYE EDWARD E KURTZ JR. GEORGE F. HARPER BY KENWAY. JENNEY. WHTER & HILDRETH Fig. 3

ATTORN EYS herein described are particularly useful as toys.

MULTIPLE STAGE ROCKET Joseph Kaye, Brookline, Edward F. Kurtz, In, Cambridge, and George F. Harper, Boston, Mass.

Application May 13, 1958, Serial No. 735,016

19 Claims. (Cl. 46-74) Our invention relates to multiple stage rockets. More particularly it relates to a two-stage rocket propelled by noncombustible propellants. Because of the utilization of noncombustible propellants, rockets of the general type However, rockets of this type may also be used for other purposes, such as the safeand inexpensive testing of equipment for use on rockets of greater range and power than toy rockets. Accordingly, while our invention will be described as applied to. av realistic two-stage toy rocket,'it-wi1l-be understood that it may also be applied to rockets used for many other. purposes, including rockets using combustible fuels.

Heretofore rockets using noncombustible propellants have been of the single stage type. In general they comprise a rocket shaped vessel, usually substantially cylindrical in shape in the central portion, witha nose section shaped as an ogive. The tail section of the rocket tapers to a nozzle or orifice through which fluid under pressure is expelled to provide thrust. Stabilizing fins are usually attached to the tail section to insure a reasonably stable flight.

In use the interior of these rockets may be partially filled with a liquid, which may be water, when the rocket nose is in the downward position. The rocket is then turned so that the nose is pointed upwardly and the space defined by the upper surface of the liquid and the upper walls of the rocket is pressurized. During pressurization the orifice in thetail section is sealed and the rocket is restrained to the launchingv mechanism. When it is desired to launch the rocket, the restraint is removed and the thrust resulting from the expulsion of fluid from the nozzle in the tail section propels the rocket in the desired direction. 7

It is well known that. multiple stage rockets can achieve greater velocities and higher trajectories than the single stage type heretofore described. In rockets utilizing combustible propellants, the second stage is arranged to fire after the thrust of the first stage has been expended. Means are also usually provided, either-in conjunction with the firing of the rocket motor, or separately, for blowing the second stage away from the first with a controlled explosion. However, this is not desirable in a safe rocket utilizing noncombustible propellants. Also, any mechanismfor controlling the time of firing of the second stage is extremely complex and expensive, and not adapted for use in rockets designed as toys. Thus, there has not heretofore been available a multiple stage rocket utilizing a noncombustible propellant. As a toy such a rocket would have appeal as being more nearly like the rockets currently in use for military, scientific and satellite purposes. For other purposes, such as equipment testing, the higher velocities and trajectories which could be achieved with a multiple stage rocket would more nearly simulate conditions which might be encountered in a rocket using combustible propellants.

Accordingly, it is a principal object of our invention ted Sta es P ts-atof release mechanism;

Fatented Mar. 8, 1960 ing nonexplosive means for separation of the stages thereof.

Another object of our invention is to, provide a rocket of the typedescribed in which release of each succeeding stage takes place after the thrust of the prior stage has been substantially diminished in order totake maximum advantage of the thrust of the prior stage.

A further object of our invention is to povide a rocket of the type described having a release mechanism'which will maintain the vtwo stages of said rocket in engagement during pressurization, but which will permit the second and subsequent stages to separate from the prior stage at the appropriate time. 1

Still another object of our invention is to provid'e'a rocket of the type described wherein the weights and operating pressures of each stage are so chosen, with respect to each other, that the second and additional stages will remain in contactwith the first stage for an appreciable time after the rocket is launched, jwithout the provision of special apparatus for holding them in engagement. 25

rocket of the type described which is simple, safe and reliable in operation, and rugged in construction so that it may conveniently be embodied in a toy rocket or reusable test equipment.

Yet another object of our invention is to provide a rocket of the type described which is economical of manufacture. Other and further objects of 'our invention will in part be obvious and will in part appear hereinafter. The invention accordingly comprises the features of construction, combinations of elements, and arrangements of parts which will be exemplified in the constructions hereinafter set forth, and the scope ot the invention will be indicated in the claims.

For a fuller understanding of the nature and objects of our invention, reference should be had to the following detailed description taken in connection with-the lease mechanism of Fig. 2;

Fig. 4 is a view similar to Fig. 3 showing-the relative positions of the first and second stages immediately after release of the holding means.

Fig. 5a is a fragmentary plan view of the nozzle end of the second stage of a rocket utilizing a second type Fig. 5b is a fragmentary side elevation of the; nozzle portion of the secondstage shown in Fig. 5a;

Fig. 6 is a fragmentary section of the upper end of the first stage illustrating the construction of this stage when a release mechanism of the second type is used, and

Fig. 7 is a detail of the slideway of Fig. 6. V

In general, two-stage rockets using noncombustible propellants made according to our invention include a relatively large first stage, generally indicated at 10 in Fig. 1 and a substantially smaller second stage, generally indicated at 12. Both stages are provided with the usual stabilizing fins, indicated at 14 and 16 respectively.

Each stage is hollow, so that pressurized fluid may be placed therein and includes a nozzle at the lower end for discharge of the propellant. Prior to launching of the rocket we provide means for holding the second stage to the nose portion of the first stage. The second stage may be sealed by the holding means if desired, butwe prefer to allow a passage to exist between the first and secondstages as will be explained more fully hereinafter. The holding means permits both stages to be pressurized, but prevents them from separating prior to launch. To accomplish this holding and separation, a slight. amount of relative longitudinal travel is permitted between the first and second stages. The oiiference in pressure between the inside and the outside of the second stage produces a' relative force which holds the second stage at one end of this travel against the holding means. However, when the first stage is launched, the inertia of the second stage causes it to move to the other end of this permitted travel. In moving from one end of this. permitted travel to the other, the holding means is uncoupled, and the second stage is free to push away from the" firststage when the relative force previously mentioned is sufficient to overcome the inertial force created by the first stage which tends to hold the second stage against its nose.

As previously mentioned, we provide a passage between the first and second stages for simplicityof pressurization. 'Utilizing a rocket whose interior is. partially filled with liquid, both first and second stages may be pressurized simultaneously. This construction, because of its. extreme simplicity, makes multiple stage rockets which are made according to our invention very economical of manufacture.

More specifically, as shown in Fig. 2, the first stage It), includes an elongated cigar-shaped body 1% having a nozzle 20 formed at its lower end. A flange 22 is provided at the lower end of the nozzle for purposes to be hereinafter described. A bulkhead 24 is provided in the interior of the body 18 near the upper end thereof and a small opening 24a is formed in this bulkhead. An upstanding tube 26 is aflixed to the upper surface of the bulkhead, the bore 26a of the tube registering with the opening 24a in the bulkhead. The body 18 of the rocket, the bulkhead 24 and tube 26 may be made of metal or a plastic having suflicient tensile strength to withstand the internal pressures within the closed chamber formed by the body 18'and the bulkhead 24. An opening 18b is formed in the upper end of the body 18 for the coupling of the second stage.

In Fig. 2 it will be observed that the nozzle 28 of the second stage is elongated and has an internal diameter sufiicient to slip over the outside of the tube 26. An O-ring 29 or other conventional sealing device is secured to the tube 26 to insure a fluid-tight seal between the second stage nozzle and the tube when the second stage is coupled thereto. The remainder of the second stage is also an elongated hollow fluid-tight body, whose only opening is the nozzle 28. If more than two stages aroused, the nose of the second stage could ofcourse be constructed in the same or similar fashion to that of the first stage. I

A flange 30 is formed at the lower end of the nozzle 28 having an annular groove 30a formed on the upper surface thereof. This groove, together with the holding means generally indicated at 34 serves to holdthe two stages of the rocket together during pressurization. In the embodiment illustrated in Figs. 2, 3 and4, the holding means includes an L-shaped rod 36 having a hook 36a formed on the upper end of the vertical leg 36b of the L. The rod is pivoted in the bracket 38, which is fixed to the bulkhead 24, the pivot point being close to the bend in the L. In Fig. 2, we have shown the rod as being pivoted on its horizontal leg, but it will be obvious that it might also be pivoted on the vertical leg 36b.

The horizontal leg 36c extends outwardly through an vopening .18c5f0rmed in the side of the body, 18 above;

the bulkhead 24, where it may readily be grasped by the operator. A spring 40 or other resilient means. is connected between the horizontal leg 36c and the bulkhead to bias the rod 36 in the position illustrated in Figs. 2 and 4.

To operate the rocket, the first stage is held nose downward and the amount of water or other fluid which it is desired to use inboth the first and second stages is fed into the first. stage through the nozzle 20. The water does not flow out the opening 24a and tube 26, while the nozzle. 20 is. sealed, since the bore of tube 26 is preferably of a sufficiently small-diameter so that the water or other fluid utilized to propel the rocket will not flow'through it. For example, because of capillary and surface tension effects, water will not flow out of an otherwise sealed container through a tube having a diameter much less than of an inch when the tube is made of glass or of certain plastic materials.

After the water is placed in the interior chamber and while the first stage is in the inverted position, the nozzle 28 of the second stage is slid upwardly around the tube 26 of the first stage. The operator then grasps the arm 36c and causes the rod 36 to pivot so that the hook 36a. engages. the groove 3.0a in the flange 30 formed. on

the base. of the second stage, thus holding the second stage in position. against the nose portion of the first stage.

A pump, or other pressure generating device, generallyindicated at 42 in Fig. 2 is then attached to the first stage nozzle. As illustrated, the pump includes a body 44 having the usualv piston therein. A handle 4-6 is attached to the piston rod 48 in conventional fashion. An outlet 50, whose outer diameter is substantially the same as the inner diameter of the nozzle 20 is formed on the pump, and an O-ring or other conventional seal is secured to the outer surface of the outlet tube to insure a fluid-tight seal between the pump and nozzle. An L-shaped fitting 52 is pivotally attached to the pump body as by a bracket 54. The catch 52a formed on fitting 52 engages the upper surface 22a of the flange 22 to restrain the pressurized rocket prior to launch.

A lanyard 56 is attachedto the fitting 5?; to pull it out of the engagement with the flange 22 when the rocket is ready for launching.

.After attachment of thepump or other pressurizing mechanism tothe first stage, and with the first and second stages pointing downwardly, the pump is operated to pump fluid from the first into the second stage. When suificient fluid is in the second stage, :both stages are turned to the nose-up position; continued pumping provides pressure for propulsion. Because the interiors of both stages are connected by the tube. 26, the pressures in the interior of both the first and second stages will be substantially equalized. it will .be understood, of course, that the two stages may be separately pressurized, in which case, the pressures in the interiors of the two stages will not necessarily be equal.

When the first stage is restrained, the second stage will exert a relative force with respect to the restrained first stage because of its internal pressure as previously described. This force causes the second stage to push away from the first stage and locks the hook 36a in the annular groove 343a as shown in Fig. 3. Also, as shown in the same figure, the spring 4G is extended and pulling on arm 36]). Note that the second stage can proceed farther down the tube 26 before it reaches the limit of its travel.

The appearance of the rocket immediately after launch is shown in Fig. 4. As illustrated therein, the second stage, because of its inertia, has slid down the tube 26 until its guiding fins 16 have engaged the nose of the first stage. The hook 360 having been freed from the annular groove 39a has been retracted by the action of the spring 4%. It will be obvious that other means than the engagement of the second stage fins by the nose of tact.

the two'stages are to remain in contact, i.e.:

the artisan as be provided to time: downward jtr'avel of the second stage. For example, the end of the second stage nozzle might bearranged to engage-bulb "h'ead24. I a Thus the second stage is nown'o longer restrained relative to the first stage. However, the second stage will not separate immediately because the acceleration of' the entire assembly forces the second stage againstthe first stage. Asthe fiuid continues to be expelled from the first stage, the pressure therein drops resulting in a decreasing thrust'trom the first stage. When the acceleration of the entire rocket decreases sufliciently due to diminution of the thrust from the first stage, the. second stage separates therefrom.

It is apparent that the hold and release mechanism herein described will operate for a two-stage rocket where the separate stages are separately pressurized and no passage is provided between the two stages. It is also apparent that a third stage could be added to the construction herein described by merely providing the secnd stage with an opening in the nose thereof and a re lease rnechanism similar to that of the first stage. The third stage, and subsequent staged-may be separately 'pressurizedif-desired. a

We have? found thatto obtain a multiple "stage rocket in which at least two stages'remain' in contact for some time afteruncouplingas a result of the acceleration of the rocket, and then separate as the acceleration of the first stage diminishes, certain relationships must be maintained between the nozzle areas, the pressures and the weights of the two stages which are to remain in con- These relationships may be determined as follows: ,If p is the gage pressure in the second stage at the time of uncoupling and A is its nozzle area, then the relative pressure force tending to separate the two stages prior to their actual separation is p A After launch this relative pressure force must be less than the force resulting from rocket acceleration and gravityactingon the mass M of the second stage if where is the acceleration of the first stage and g is the gravitational acceleration.v

The thrust T of the first stage at the time of uncoupling equals the total mass of both stages multiplied by their acceleration, i.e.:

where M is the mass of the first stage at the time the I stages are uncoupled.

" Solving Equation 2 for yields:

T, Mt+Ml) l Substituting Equation 2a in 1a,

. T V tftw iwfil l W and W .being equal respectively to Mg and Mg and being-the values'ofthe weight of each stage at the l time of uncoupling.

Equation 3' may befurther simplified to;

A 3a K Wt+WQ which indicates that for the two stages to remain in contact after they are otherwise free to separate, the relative pressure force tending to separate them, p A must be less than the ratio of the second stage weight to the total rocket weight multiplied by the thrust, T. The

asst-ass the first stage and Vj'is" the"'average' velocityof the first stage jet 'over the cross "sect1on.' '-It, is known that n1 V,A,, where .p is the fluid densityin the first stage ,and' A; is'the' area ofthe jet being. emitted from the first stage. A, is related to the nozzle area of the first stage. A by a nozzle coefiicient C which depeuds upon nozzle shape. *Thus ,Aj=CA1- The nozzle coefficient C is defined and representative values are given for various nozzle configurations on page 157 of Hunsaker and Rightmire, Engineering Applications of Fluid Mechanics Thus, the thrust T at the time of uncoupling may be determined as T It is well known in fluid mechanics that (V. =2(%) to where 12 is the pressure in the first stage; at the time of Equation 8 defines the necessary: conditions for the second and any additional stages of a multiple stage rocket made according to our invention to remain in contact with the first stage after the two stages are uncoupled, i.e., free to separate, measured in terms of areas, weights and pressures. I

Where a passage connects-the two stages of the rocket for ease in pressurization and the stages are uncoupled substantially at the time of launch (as previously explained), 2 12 will be substantially equal and Equation 8 simplifies to:

A3 W2 Wri- W2) (9) It will be observed that the greater the inequality given by Equations 8 and 9 the more securely the two stages will remain in contact. It will also be notedthat by substituting for W in these equations the weight of all additional stages, the equation may be readily .applied to multiple stage rockets having more than two stages.

Further, if uncoupling takes place substantially at the time of launching, as has been discussed in connection with the release mechanism illustrated inFigs. 2, 3 and 4, the W and p; are the initial values of weight and pressure of the first stage. If uncoupling takes place after launch, W and p can be readily determined since they are functionally related. W and p of course remain at substantially their initial values until after separation occurs. 7

Turning now to Figs. 5a, 5b, 6 and 7, we have here illustrated an alternative coupling mechanism which ,might be used in place of themechanism illustrated in Figs. 2, 3 and 4. As shown in Fig. 6, the bulkhead 24 which forms the nose end of theinterior chamber of the first stage 10, has a circular well formed therein to receive the nozzle 28' of the second stage of the rocket. An opening'24a' is provided in the bulkhead and a tube 26', only a portion of which is shown in Fig. 6 Whose bore registers with the opening 24a is attached thereto; an O-ring (not shown) or other sealing device is secured to the tube 26'. The tube and the sealing device perform the same ;.functions as described in connection'with the previous embodiment.

s It will be observed that no flange is provided on the second 'st'age nozzle inIthis construction. Rather, a slider 7 hav ng ei hane sho n i Fig 54 and 5 is orm thereon. This. slider eng e the l w y r ned iri the circular wall of the well 70. Fora better understanding'of'the operation of the slider and slideway, reference should be had to Fig. 7, which represents a formed in the side-wall of the well 70 having substantially the shape shown in Fig. 7.

In use, the nozzle 28' of the second stage 12 of the rocket is inserted in the-well 70 with the tube 26' passing into the nozzle orifice 28a. As a. result of this insertion, the slider 72 enters the passage 74a and follows the passage downwardly until the sloping lower surface 72a of the slider engages thelower surface 74b of passage 74a. The force exerted in putting the two stages together causes the slider to follow the sloping surface 74b downwardly until the vertical surface 72b of the slider engages the vertical surface 740 of the passage. With the two stages in this position pressurization may be started.

As the pressure in the second stage builds up, the second stage tends to push away from the restrained first stage as previously described and the slider moves upwardly along the vertical surface 740 until its upper sloping surface 720 engages the sloping surface 74d. The space between the upper end of surface 740 and the surface 74:! immediately above it is slightly greater than the extent of the surface 72b. Thus the pressure will cause the slider 72 to travel up the sloping surface 74d, until the sliders vertical surface engages the short vertical surface 74a. The second stage is locked in this position (illustrated by the sectional view of the slider in Fig. 7) by the relative pressure force previously mentioned which tends to separate the two stages and the second stage remains in this position during pressurization.

Upon launching of the multiple stage rocket, the second stage will be forced downwardly toward the first stage, as a result of the acceleration as previously explained. As a result of the motion of the second stage, the surface 72b of the slider will be disengagedfrom the surface 74a and its lower surface 72awill engage the sloping surface 74f. The carnming action of the two sloping surfaces will cause the slider to move until its surface 72b engages the vertical surface 74g. The second stage will remain in this position ready for release, while the first stage continues to accelerate. When the thrust of the first stage diminishes enough for the second stage to separate therefrom, the second stage moves upwardly away from the first stage. As it does so, the upper surface 720 of the slider engages the sloping surface 74h of the passage and causes the slider to enter the substantially vertical passage 74f. When the slider is in the passage 741', the second stage rocket is free to separate from the first stage.

Inthis fashion, the second stage is coupled to the first stage during pressurization, it is uncoupled by the movement of the second stage toward the first stage upon launching of the rocket, and finally separates from the first stage when the first stage thrust has suificiently diminished. It Willbe understood, of course, that the construction described herein, the lateral movements of the slider 72 in the passage 74 as described in connection with Fig. 7 will actually be movements along the circumference of a circle, with accompanying rotation of the second stage with respect to the first stage.

It will also be understood that a number of connected passages similar to passage 74 may be formed about the periphery of the well 70 as illustrated in Fig. 7. Thus in the event that the slider 72 isinserted in the passage 741 its lower surface 72 1 will engagethe sloping surface '75a of the passage 75 and willthereby be properly positioned for the release cycle to take place. 'If connected passages are formed about the entire prepihery of well 70, theslider may be inserted in any of them. If they donut extend continuously about the periphery, then the exit passage, corresponding to passage 74i, of the last connected passage, is marked to indicate that slider 72 should not be inserted therein.

It-will thus be seen that we have provided a simple and extrernley inexpensive construction for a multiple stage rocket utilizing noncombustible propellants. Rockets made according to our invention have been described particularly with respect to two different embodiments of two-stage rockets, but it will be obvious to those skilled in the art that additional stages may be added utilizing the same constructions.

In our constructions, the second and first stages both consist of hollow vessels having a nozzle at one end thereof. They are secured together by a coupling means which permits a small amount of relative travel between the stages. During pressurization, the force tending to separate the two stages of the rocket holds the second stage at one end of the travel, locking it in position. Upon launching of the rocket, the second stage is forced to the otherend of the travel, which releases thecoupling means; the second stage is then free to separate from the first stage when the thrust of the first stages diminishes sutfieiently so that the relative force between the two stages can overcome the inertial force tending to hold the two stages together.

In order to permit ready pressurization of the. two stages, we also provide a narrow passage connecting them. This passage is suficiently constricted to prevent .the how ofan appreciable amount of propellant through said passage from the second stage in the small time required for the first stage to complete its period of acceleration, thus permitting the propellant in the second stage to seal the passage after pressurization.

We have also found that certain relationships must exist between the first and second stage nozzle areas, pressures and weights at the time of uncoupling, if the two stages are to remain in contact as a result of rocket acceleration. When these relationships are observed, the second stage release is determined by the time the entire rocket acceleration diminishes to a value less than that required to hold the second stage to the first.

It, will thus be seen that the objects set forth above, among those made apparent from the preceding description, are efficiently attained and, since certain changes may be made inthe above constructions without departing from the scope of the invention, it is intended that all matter contained in the above description or shown in the accompanying drawing shall be interpreted as illustrative and not in a limiting sense.

It is also to be understood that the following claims are intended to cover all of the generic and specific features of the invention herein described, and all statements of the scope of the invention which, as a matter of language, might be said to fall therebetween.

Having described our invention, what we claim as new and desire to secure by Letters Patent is:

l. A rocket including at least two stages comprising, in combination, a first stage including a storage vessel for pressurized fluid, said vessel having a discharge nozzle for propelling said rocket formed in a portion thereof, a second stage including a storage vessel for pressurized fluid said vessel having a discharge nozzle for propelling said stage formed in a portion thereof, means associated with said rocket for holding said first and second stages in engagement after pressurization, with said first and second stage nozzle not in engagement, means for releasing said holding means, the ratio of the nozzle area of said second stage to the nozzle area of said first stage being selected such that said second stage is held in engagement with said first stage after release of said holding means by the force resulting frs as s s s tisn t a ttfir t st rocket is so designed that:

. i Thecombinatidnjdefined inclaim- 1 in'which said rocket is so designed that:

where: A is the nozzle area; of said second stage, A; v

is the nozzle area of saidfirst stage, C is the nozzle coefficient cfsaid first stage,'W is the weight of .said

cinemas Lber adapted to enclos ejfluid under 'pressurefa discharge nozzle formed in one part of said chamber-for discharge said first stage at the time of release of said holding at the time said holding means isreleased.

3; A rocket including at'least two stages comprising, m combination, afirst stagein'cluding a storage vessel for pressurized fluid, said vessel having aj discharge nozzle for propelling said rocket'form'ed in a portion .thereof, a second stage including a storage vessel for pressurized fluid, said vessel'having a discharge nozzle in engagement, a passage interconnectingsaid first andsecond stages when said stages areheld'in engagement, means for releasing saidholding means, the ratio of the nozzle area of said second stage to the nozzle area of said first stage .being selected such that said second stage is held in engagement with said first stage after release of said holding means by the force resulting from acceleration of said rocket.

4. The combination defined in claim 3 in which said where: A: is the nozzle area of said second stage, A is the nozzle area of said first stage, C is the nozzle coefficient of said first stage, W is the weight of said first stage at the time saidholding means is released, W is the weight of said second stage at the time said holding means is released, p is the gage pressure in said first stage at the time of release of said holding means and 12,, is the gage pressure in said second stage at the time said holding means is released.

5. A rocket including at least two stages comprising in combination, a first stage, including a storage vessel, the walls of said vessel defining a hollow interior chamber adapted to enclose fluid under pressure, a discharge nozzle for propelling said stage formed in one part of said chamber for discharge of said fluid, a second stage, said second stage also including a storage vessel, the walls of said vessel defining a second hollow interior chamber adapted to enclose fluid under pressure with a discharge nozzle for propelling said rocket formed in one portion thereof, means for coupling said first stage and said second stage in fixed relative relation with the nozzle of said second stage directed toward a nonnozzle portion of said first stage prior to release of said rocket, means responsive to the acceleration of said rocket after launching thereof .to'release said coupling means and thereby free said second stage for separation from said first stage.

6. The combination defined in claim 5 which includes a passage interconnecting the storage vessels of said first and second stages when said. stages are in engaged relationship.

7. The combination defined in claim 5 in which said coupling means are released by the acceleration of said rocket which occurs substantially at the time said rocket is launched.

8. A rocket including at least two stages comprising in combination, a first stage, including a storage vessel,

' the walls of said vessel defining a hollow interior chammeans and p: is the gage pressure in said second stage of saidfluid to propel said rocket, a second stage, said second stage also includingastorage vessel, the walls or said vessel defining a second hollow interior chamber adapted to enclose fluid under pressure with a discharge nozzle for saidfluid to propel said second stage Iformed m. one portion thereof, means for coupling said first said rocket, said coupling means permitting a small travel of said stages with respect to'each other, and said coupling means being locked when said second stage isIat one end of said travel, the acceleration of -said rocket upon launching causing said second 1, stage to move to the other end of said travel to thereby uncouplesaid second 'stageland permit said second stage to separate from said first stage. v

9. A rocketincluding at least two stages, comprising, in combinatioma' first stage including an elongated storage vessel, the wallsof said vessel defining a hollow interior chamber adapted tojenclose' fluid under pressure,

said first stage and said. second stage together in end to end relationship, with the nozzle of said' second stage engaging the non-nozzle end of said first stage prior to launching said rocket, said coupling means, permitting a small longitudinal travel of said stages with respect to each. other,,said coupling means being locked when said second stage is at the end of said travel most distant from said first stage, the launching of said first stage causing said second stage to move toward said first stage to the other end of said travel, thereby uncoupling said second stage and permitting it to separate from said first stage.

10. The combination defined in claim 9 which includes a passage interconnecting the storage vessels of said first and second stages when said stages are in engaged relationship.

11. A rocket including at least two stages, comprising, in combination, a first stage including an elongated storage vessel, the walls of said vessel defining a hollow interior chamber adapted to enclose fluid under pressure, a discharge nozzle formed in one end of said vessel for discharge of said pressurized fluid, a second stage, said second stage being smaller than said first stage and including an elongated storage vessel with a discharge nozzle formed at one end thereof, a flange formed on the periphery of said nozzle, means for coupling said first stage and said second stage together in end to end relationship, with the nozzle of said second stage engaging the non-nozzle end of said first stage prior to launching said rocket, said coupling means including an arm pivotally attached to said first stage having a hook on one end thereof, said hook being adapted to engage the flange on said second stage nozzle as said arm is rotated about said pivot, resilient means biasing said arm to a position of non-engagement with said flange, and a handle attached to said arm whereby said arm may be rotated about said pivot to engage said flange, said hook being held in engagement with said flange against said resilient means by the relative pressure force tending to separate said first and second stages prior to launch, launching of said first stage causing movement of said first and second stages toward each other, to thereby cause said flange to disengage from said hook, said arm thereby being retracted by said resilient means.

12. The combination defined in claim 11 in which an annular groove is formed on the inner surface of said flange.

.rs tat .isslssli t l a w st es si t sing, in. combination a. first stage including an elongated storage vessel; thewalls of said vessel defining a hollow interior chamber adaptcdv to enclose fluid under pres sure, a discharge nozzle for propelling saidrocliet forrned in one end of saidlvessel for discharge of said pressurized fluid, a bulkhead for rn ed across the -non-no zzlc end of said-first stage, an opening formed in said bulkhead, a tubular member secured to theoutcr'surface of I said bulkhead, the passage in said tubular member regcludes sealing means between said second stage nozzle and the tubular member of said first stage.

15. The combination defined in claim 13 in which an O-ring sealissecurcd to the outer surface of said tubu lar n eruber, to thereby seal the nozzle of said second stage and said tubular member.

16. The combination defined in claim 13in which the diameter of the passage formed in said tubular memher is sufiiciently small so that liquid in said second stage,

will not flow therethrough when said second stage is otherwise sealed.

17. A rocket including at least two stages, comprising, in combination, a first stage including an elongated storage vessel, the Walls of said vessel defining a hollow .ists ist =9 2 ,as s ts tbk cl'qss aqfluid dq p sure, a discharge nbzzle formedin fend st'saiid 'v e s* sel for discharge of said pressurized fluid, a'seco'nd stag e, said second stage. including an elongated storage vessel having a discharge nozile formed at one end thereof, means adapted tocouple said first tand second stages togather in fined relatiye relation, said coupling means including a protruding slider formed on one of said stages anda'tortuous passage formed in the other of said stages, said passage torrning ta slideway for said slider when said stages are in engagement, said siideway including an inlettpassage for said slider, when said stages are placed inengagement,pressurization of said stages causing said slider to move from said inlet passage to a locked position in saidslideway, and the acceleration of said rocket after launching thereof causing said slider to moverfrorn said loclged position to an outlet passage of saidslideway, said firsta'n d second stages being free to separate when. said slider is in said outlet passage.

l8, combination defined in claim 17 in which a plurality of said tortuous passages are formed on one 'of-fsaid stages, theioutlet passage of one slideway being the inlet passage of thenext succeeding slideway.

19 The combination defined in clairn 17 in which a pa a 'im onsasts th q ass vessels vfwsaid first and second stages when said stages are in engagement.

References ,Cited in the file of this patent UNITED STATES PATENTS 2,804,823 Iablanslcy Sept. 23, 1957 2,829,491 Teague Apr. 8, 1958 FGREIGN' PATENTS 161,579 Australia Mar. 1, 1955 

